Novel gate-controlled bipolar composite field effect transistor with large on-state current

Abstract

Novel gate-controlled bipolar composite field effect transistors (GCBFET) based on vertical MOSFETs are proposed and investigated in this paper for the first time, named VD-GCBFET and U-GCBFET, respectively, which feature the base-gate short connection mode instead of the conventional base-source short connection mode. When the devices are turned on, the composite bipolar junction transistor (BJT) provides an additional holes injection path, which is conducive to obtaining larger forward on-state current. Two conductive paths provided by the composite BJT and MOS structure not only improve the integration degree, but also greatly increase the forward on-state current while the breakdown mechanism remains unchanged. The simulation results show that, with the same structural parameters, the proposed GCBFETs have the same breakdown voltage and much lower threshold voltage compared with the corresponding vertical MOSFETs. Meanwhile, the proposed GCBFETs gain much larger forward on-state current which is over two orders of magnitude higher than that of the corresponding vertical MOSFETs. Moreover, due to the introduction of extra holes by the composite BJT, the proposed GCBFET has similar slow switching speed as IGBT.